SOUTH KOREA - South Korea has pressed China to step up its own crackdown against illegal fishing by Chinese fishermen near the Yellow Sea border with North Korea, an official said, following mounting complaints against the illegal Chinese fishing.

A number of Chinese fishing boats allegedly entered South Korean waters near the sea border and stole or damaged fishing gear and nets installed by South Korean fishermen this month, causing property damages worth 362 million won (US$331,957), according to maritime police, reports .

Seoul's foreign ministry sent a diplomatic letter to the Chinese embassy this week, calling on Beijing to "swiftly root out the illegal fishing by Chinese boats in waters near the Northern Limit Line (NLL) through a thorough crackdown," the ministry official said on the condition of anonymity.

The NLL refers to the tense Yellow Sea border, which has long been a flashpoint of inter-Korean conflicts as well as rich fishing grounds.

The official said the illegal Chinese fishing near the NLL is "worrisome in terms of security."

North Korea has never recognized the NLL, which was drawn unilaterally by the U.S.-led United Nations Command when the 1950-53 Korean War ended, and demands that the line be drawn farther south.